The Problems with Peat
Seed starting time is upon us, and many of us may buy a seed starting mix without putting much thought into its composition. We naturally want “the best” that we can find, and traditionally this has involved a mixture with peat. Many American home gardeners are unaware of the problem with using peat and we have become so dependent on it in our gardens. So, what's the big deal and what are the problems with using peat?
Peat is non-renewable and unsustainable.
Humans have used peat for 2,000 years for heating and cooking, where wood was limited (Scottish Highlands, The Fens of England, Rural Ireland, Netherlands, and Germany). The peat was cut by hand with a “tusker”, a spade-like tool, in the spring. It was left to dry and stacked for use in winter. In the 1850’s peat was extracted mechanically as the need was increased during the peak industrialization and colonialism of the Victorian era. The use for peat began to wane with the rise of coal and oil. Conversely the high demand of electricity in Ireland in the 1940-50’s saw another large-scale peat extraction for power plants. Peatmoss has been a fixture in horticulture since the 1960’s. Nurseries existed for centuries and plants were sold primarily locally and seasonally. Seeds, especially vegetables, were sold via mail order catalog. After WWII suburban development increased the demand for residential landscaping plants. The first retail garden centers, in the UK and US, opened in the 60’s. Plastic potted plants as opposed to heavy terracotta pots and bare roots were sold year round. The lightweight soil-less medium of peat moss revolutionized how plants were transported. Most of the world’s peat is used in horticultural greenhouses and gardening. Peat is used in seed starting, potting mix, and as a soil amendment. Plants respond well in peat. We love peat in the US and we use 1.5- 2 million tons of it a year (usgs.gov).
Peatlands can be found all around the world. Peatland bogs are nutrient poor, high in acid and are kept alive by rainwater. It grows like a blanket above water in rainy and wetter conditions. It rises and falls throughout the year. The top layer (living layer) is made up of many types of moss, grasses, and low shrubs and holds the bog together. The Sphagnum moss on the top layer is used as a soil amendment and often used by the floral industry. The acidic conditions of the top layer slowly causes the living material to decompose into the lower layer while also, at the same time, producing more living moss. The layer below was once the top layer and continues to decompose. This is dense and full of water and is the layer of peat moss used extensively in horticulture. To extract the peat you have to go ½ meter deep or 20 inches. It takes 500 years minimum to create this peat as it is a slow grower, growing only 1 mm per year.
Peatlands store 30% of the world's carbon, second only to the ocean. Peatland helps mitigate storm water, in the case of flash floods. The moss soaks up the water preventing run-off. The Sphagnum moss acts as a filter that keeps the earth cool, provides clean air to breathe, and water clean. When the bogs are drained and the peat is exposed it releases carbon into the atmosphere. In the UK, 80% of the bogs are degraded and releasing greenhouse gasses. Damaged bogs admit 2 billion tons of Co2 per year, according to the UN (Financial Times 2025).This disturbance raises global temperatures which further exacerbates the drying out of the bogs. Opportunistic trees begin to self seed on the bare soil and the roots begin reaching for the bogwater below, contributing to the drying out of peatland.
Restoration is slow and falling short. In the UK they are attempting to re-wet the bogs and raise the water levels. Other efforts in the UK include a full ban of the use of peat. The Royal Botanic Gardens at Kew has been peat free since 2003 and the use of peat has been “banned” by the UK horticultural industry, although not yet legally binding. The Royal Horticultural Society (RHS) hosts of the Chelsea Flower Show has delayed its ban on peat from 2025 to 2027, implementing instead a “No New Peat Rule”. In the meantime, UK gardeners are trying to find other sustainable alternatives to peat.
The largest exporter of peat is Latvia which is providing 20% of the world's volume followed by Canada at 13%. US peat comes from Canada and is a potential target for the US tariffs, at 25%. The United States imports 85% of the peat moss from Canada. Greenhouse growers, farmers and consumers are highly dependent. AmericanHort is urging lawmakers to designate peat as “critical mineral” which would reduce the tariff to 10%.
Horticulturalists like the way plants respond to peat, it provides good aeration and holds on to nutrients without excess salt. Coconut coir, a common alternative, holds on to water and has good infiltration, but is inert, lacking nutrition. Coir is salty and contains chemicals that are used during processing, which needs to be flushed out before using. Coir comes from India and Sri Lanka and has a large carbon footprint. Fox Farms carries coir-based mixes, and some are tripled washed.
Espoma Organic Seed Starter is 80-90% Canadian sphagnum peat moss, perlite, limestone, ecto and endo mycorrhizal fungi, and yucca extract. Pro mix organic seed starting mix has a similar recipe that includes peat moss and coir, but no yucca extract. I have used Organic Mechanics Seed Starting Blend and find it to be quite good. It contains aged pine bark, rice hulls, earthworm castings, coir, and organic fertilizer. I also want to try making my own mix with my homemade leaf mold compost as the main ingredient (it’s hyper local and free). In the meantime, let’s continue to read the ingredients on the potting mix bags and match the mix to the needs of our plants.
Thanks for reading. Want to Dig Deeper?
What I am reading: Peatlands, A Journey Between Land and Water by Alys Fowler (2025), Hodder Press.
What I am watching:
Clara Bog: Peat land history and conservation - YouTube
How we're working to protect precious peatlands in the North West of England - YouTube
